diff -urN a/include/interface.h b/include/interface.h
--- a/include/interface.h	2008-02-21 10:20:29.000000000 +0300
+++ b/include/interface.h	2010-12-03 23:58:15.000000000 +0300
@@ -21,7 +21,14 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * @(#) $Header: /cvsroot/trafd/trafd/include/interface.h,v 1.3 2008/02/21 07:20:29 lorf Exp $ (LBL)
+ * @(#) $Header: /cvsroot/trafd/trafd/include/interface.h,v 1.4 2010/10/31 02:40:00 Serg79 Exp $ (LBL)
+ *
+ * Revision 1.4  2010/10/31  02:40:00  Serg79
+ * Added support for PPP interfaces in Linux.
+ *
+ * Revision 1.3  2008/02/21  07:20:29  lorf
+ * Initial revision
+ *
  */
 
 #ifndef tcpdump_interface_h
@@ -132,6 +139,10 @@
 #endif
 
 extern void processing_ip(const uint8_t *, u_int);
+#ifdef __linux__
+extern void linux_sll_if_print(u_char *, const struct pcap_pkthdr *,
+		const u_char *);
+#endif
 extern void ether_if_print(u_char *, const struct pcap_pkthdr *,
 	const u_char *);
 extern void null_if_print(u_char *, const struct pcap_pkthdr *, const u_char *);
diff -urN a/lib/interfaces.c b/lib/interfaces.c
--- a/lib/interfaces.c	2004-11-17 12:06:31.000000000 +0300
+++ b/lib/interfaces.c	2010-12-04 00:01:02.000000000 +0300
@@ -17,6 +17,15 @@
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * $id: interfaces.c,v 1.1 2010/10/31 02:40:00 Serg79 Exp $
+ *
+ * Revision 1.1  2010/10/31  02:40:00  Serg79
+ * Added support for PPP interfaces in Linux.
+ *
+ * Revision 1.0
+ * Initial revision
+ *
  */
 
 #include <sys/param.h>
@@ -47,6 +56,9 @@
 
 #include <stdio.h>
 #include <pcap.h>
+#ifdef __linux__
+#include <pcap/sll.h>
+#endif
 
 #include "ethertype.h"
 #include "interface.h"
@@ -70,6 +82,9 @@
 		{ ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 		{ null_if_print,        DLT_NULL },
 		{ raw_if_print,         DLT_RAW },
+#ifdef DLT_LINUX_SLL
+		{ linux_sll_if_print,   DLT_LINUX_SLL },
+#endif
 		{ NULL,                 0 },
 };
 
@@ -87,6 +102,28 @@
 		return NULL;
 }
 
+#ifdef DLT_LINUX_SLL
+/* Linux specific PPP printer */
+void
+linux_sll_if_print(u_char *user, const struct pcap_pkthdr *h, const u_char *p)
+{
+	u_int caplen = h->caplen;
+	u_int length = h->len;
+	const struct sll_header *sp = (const struct sll_header *)p;
+
+	if (caplen < SLL_HDR_LEN)
+		return;
+
+	packetp = p;
+	snapend = p + caplen;
+
+	length -= SLL_HDR_LEN;
+
+	if (ntohs(sp->sll_protocol) == ETHERTYPE_IP)
+		processing_ip((const u_char *)(p + SLL_HDR_LEN), length);
+}
+#endif
+
 /*
  * This is the top level routine of the printer.  'p' is the points
  * to the ether header of the packet, 'tvp' is the timestamp,